Sunday, January 17, 2016

Removing the Front Frame Rail/Shock tower assembly

Probably the most intimidating part of the project so far is the removal of the frame rail/shock tower assembly. As I've noted everything on the right side of the engine bay is damaged in some way and needs to be replaced.

Fortunately, this entire assembly is now reproduced as a single piece, so I'm going to remove my old broken parts as one assembly and install the new one in its place. After this, I'll remove and replace the radiator support as well, so I don't have to worry about being careful in during the removal about causing any collateral damage to the radiator support.

The new piece is has the full frame rail, the front (battery) apron, the rear (hood hinge) apron, shock tower with extra support plates (based on what Ford installed on big-block cars - but you don't get a choice in this, it just comes this way), the sway bar mount, a coil spring cover, and the rear apron-to-cowl brace. It's all assembled in a jig to correct dimensions (right?) and covered in e-coating. The new assembly weighs in at 50 lbs, whereas the original I remove here is only 45 lbs, about 5 lbs lighter. The shock brace plates on the new assembly are most of that difference I bet.

The diagonally-mounted strut rod support (connects the bottom of the frame rail to the radiator support) will be kept since it's already in the correct place per the frame shop measurements (and mine). So it will stay mounted to the car by at least one end through this entire process. I'd worry about getting it mounted wrong If I took it off, and that's bad - the strut rod location is critical for proper suspension alignment. If it was welded back in all cockeyed, the car might never track straight as it went down the road.

So, let's get to it - lots of pictures in this one, I'll keep the commentary short and point out mistakes/pointers as we go.

Where the front apron met the radiator support was already a mess from a poorly-repaired previous accident. Those aren't factory welds, and notice the big gap - these pieces should be in contact all the way top to bottom. I cut these welds and the few remaining spot welds holding the front of the apron to the rad support.

At the very front of the frame rail, I had to cut an access hole to get to the hidden 4 spot welds that connect the rad support crossmember to the inner frame rail. I thought about this for a while and finally decide since all these pieces are being replaced, this was the best answer.

Access hole opened up and now you can see the hidden spot welds. Of course, now you have to reach in there and drill them out...

This sucked - no two ways about it. And, as I'll soon show, possibly entirely unnecessary.

Still at the rad support/crossmember interface at the front of the frame rail. There are spot welds on top, on the front and on the bottom still to drill out. Here you can just see the little indentions where the factory welds are located.

And on the front of the crossmember...

And on the bottom of the frame rail. I followed along with the factory weld and sealant manual and found it pretty accurately described the location and quantity of every spot weld I needed to remove. Starting to drill out the welds...

Once I had all the welds drilled out at this interface, I still needed to separate the pieces with a 5-in-1 painters tool to get some daylight in between the parts. Interior of the frame rail doesn't look too rusty, no real rot in there. Pity it's all bent up...

More prying/cutting of drilled spot welds for final separation...

Here is where to sway bar mount connects to the strut rod mounting. There are two spot welds plus a bead weld on the front that needed to be cut (yellow chauk). The spot welds were easy, but the bead weld resisted all my clever tricks...

Here's how I finally got around that stupid bead weld - I just sectioned out the part of the sway bar mount that was in the way. My new assembly also comes with a new sway bar mount, so no worries.

This is the bottom view where the strut rod mount connects to the bottom of the frame rail. 5 spot welds - I drilled them all the way out because I'll use the holes on the bottom for my plug welds later for reassembly.

This is the brace that holds the top of the rear apron to the cowl. There's only about 8 spot welds here to remove but I have other issues - I think the collision damage has pushed this back a little and creased the end of the cowl where this brace connects to it. I may have to beat the cowl panel back into shape before I can install the new brace here.

I love that everytime I remove a piece I find dirt/crud/rust underneath it. No, this doesn't make me worry at all...

Old vs. New apron brace. Again, new part was included in the assembly I ordered.

The frame rail also attaches to the firewall/toeboard area. I drilled these all the way out from inside the cabin so I could to my welding at a regular 45-degree angle. My hope is that the new frame rail will line up its assembly flange with these holes, just like it did at the factory, and I can plug weld through these holes to the frame rail.

This is where the rear apron meets the firewall. While there are lots of spot welds holding this interface together, I just zinged a cut from top to bottom so could remove the flange after getting the big assembly out of the way first. As it is here, I can't really get to these welds from the outside, and drilling them from inside under the dashboard would be just awful.

The weld and sealant manual is very handy BUT you really should thumb through the whole thing before you start just disassembling the car with reckless abandon. While the spot weld assembly pages are pretty much in order of how the car was built, there is a section at the back that has a lot of supplemental bead welds, fillet welds, and other miscellaneous welds that you may not know about. This one above, where the rad support meets the inner frame rail is one of those little nuggets in the back of the book. Again, no good way to cut that, but both pieces will be replaced, so again I just zinged a cut around the vertical bead weld.

Ok, blog confessional time. I had planned on drilling all these welds and just pulling the assembly out to the side. But the jig was in the way. Oops. So I decide to pull out forward - but now the radiator support and crossmember are in the way.

No big deal - just cut all the way around the perimeter of that interface with a whiz wheel and we're done. Please note however, this just made all that spot weld drilling and cutting I did earlier up here totally unnecessary. I could have just made these 6 cuts and been done with it instead of screwing around with the 15 spot welds. Frak.

Cutting crossmember just inside the superfluously-cut spot welds.

See how much easier this is?

Here we go. All the welds are cut. Now all that's left is the pulling...

Blamo! The car is now officially undriveable. I finally found a theft-deterrent that works. And in my town, that's really saying something.

The old assembly in all its glorious mess. I plan to surprise Good Lady Wife and turn this into a piece of yard art. She's a creative, right-brain girl, I'm sure, she'll love it.

Total time to do this removal was about 16 hours. I burned up two spot weld bits in the process and managed to get metal shavings in my eye despite double-eye protection. No harm, but sorta irritating (wait, are puns still allowed on the internet?)

2 comments:

I've just spent the last two hours reading and taking notes of your build. It's perfect for me, as I too am restoring a '67 fastback, although mine has suffered less. Is there a way we can get in touch and talk shop ?

I'm glad you're finding it helpful! Frankly, if you're looking for more advice and help, you'll be light-years ahead if you head over to some of the forums on Vintage Mustang Forums or Classic Mustangs @ MustangFourms .com - there is lots of good advice (and support) over there. Those are some of the places I hang out/lurk around to get help. The links are on the sidebar if you need them. Good luck!